High speed toggle driver pivoted veneer clipper



June 16, 1959 v. E. ANDERSON HIGH SPEED TOGGLE DRIVER PIVOTED VENEERCLIPPER Filed Oct. 10, 1955 5 Sheets-Sheet l ATTO/P/VE) June 16, 1959 v.E. ANDERSON 2,890,749

HI I GH SPEED TOGGLE DRIVER PIVOTED VENEER CLIPPER j Filed Oct. 10, 1955s Sheets-Sheet 2 FIG. 2

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June 16, 1959 v. E. ANDERSON I 2,890,749

' HIGH SPEED TOGGLE DRIVER PIVOTED VENEER CLIPPER Filed Oct. 10, 1955 3Sheets-Sheet 3 FIG. 4.

HTTOIP/VEV United States Patent HIGH SPEED TOGGLE DRIVER PIVOTED VENEERCLIPPER Victor E. Anderson, Springfield, reg., assignor to Clear FirProducts Co. Inc., Springfield, 0reg., a corporation of OregonApplication October 10, 1955, Serial No. 539,529 1 Claim. ((1164-43) Thepresent invention relates to a high speed veneer "clipper andparticularly to a novel anvil and knife combination adapted to effectefiicient and speedy clipping of continuously moving sheets of woodveneers into desired panel sizes. The invention is also adapted for therapid cutting out of veneer defects.

Many veneer clippers have been proposed for cutting continuously movingsheets of wood veneers. Generally, they comprised means for rigidlysupporting a veneer cutting station with means for delivering veneersheets to said station, the station being comprised of an anvil and aknife assembly cooperable therewith. The knife was usually actuatedvertically in guillotine-like fashion and was adapted to clip veneersupported beneath it on an :anvil, the knife contacting the surface ofthe anvil on 'the down stroke after cutting through the veneer. The downstroke of the knife blade had to be controlled very carefully so as tominimize impact of the knife edge with the anvil and to minimize knifewear. The anvil sup port Was considered important as it enabled theobtaining of a clean cut across the veneer substantially free from ripsand tears. However, the combination had its disadvantages in that theknife would dull easily and had to be resharpened frequently, thusincreasing down time. To overcome this ditiiculty, resilient anvils wereproposed, for example anvils made of hard resilient rubber. Thisimprovement, while it prolonged knife life somewhat, actually merelyshifted the problem to the anvil which required maintenance as the knifewould cut the rubber with the net result that the anvil eventually hadto be replaced. Even then the knife did not always maintain a sharpedge.

The use of a vertically moving knife also had its disadvantages in thatit required high vertical side supports, for example slide or rollguiding supports to control the up and down movement of the knife, whichnecessitated considerable head room. For best cutting performance, theknife required heavy, massive back-up means which had to be moved bodilywith the knife.

Such machines, because of their high center of gravity, were subject tovibration and were noisy. Furthermore, the machines were not as quickacting as desired because of the inertia prevailing in the heavy back-upmeans and in the mechanism operating the vertically sliding knifeassociated with the back-up means. Long operating strokes had to he usedin order to oscillate the knife up and down because of the considerableweight of the knife assembly.

The present invention differs from prior veneer clippers in that itprovides for a novel arrangement of the anvil and clipper assemblyresulting in considerable saving in head room. The machine, while it hasa heavy knife assembly, has a low center of gravity and operates withminimum vibration and noise.

The invention provides an entirely difierent type of knife arrangementat the cutting station where a pivotally mounted carriage is employed tocarry the knife which rocks by the axial turning or oscillation,clockice wise or counterclockwise, of a massive longitudinal memberwhich acts as a stable pivot point, the center of gravity of thecarriage being maintained near the pivot so that the rocking of thecarriage is effected easily, quietly and quickly. By so balancing theknife assembly, the carriage, which responds easily to an appliedrocking force, enables the knife to cut at speeds of up to about 500oscillations per minute with minimum vibration, a speed not generallyapproached by prior clippers. In other words, the heavy and rigid knifeassembly is not displaced bodily as in prior clippers but, on thecontrary, is rocked, with the weight of the assembly substantiallybalanced about the pivot.

The rockable carriage construction enables the use of a heavy rigidknife that does not spring out of line when contacting a veneer sheetduring cutting. Furthermore, the heavy rigid knife blade insures a cleancut and has a long tool life.

The knife blade is situated on the carriage so that its longitudinalaxis is substantially parallel to the longitudinal axis of the massivemember about which it pivots. This arrangement enables sensitive andaccurate control of the knife, whereby it can be easily brought downinto cutting relationship with the anvil without striking it with anysubstantial force and in many instances hardly striking it at all.However, it is preferred that a cutting edge of the knife be broughtdown closely adjacent and slightly past an edge of the anvil for efii--cient cutting. This type of cutting or shearing affords optimum toollife for both the anvil and the knife, since neither hardly touches theother during cutting in this embodiment of the combination. The rockingincrement is small and enables the knife to be retracted quickly for thenext cut.

These and other features will more clearly appear when taken inconjunction with the attached drawing in which:

Fig. l is a plan view showing the pertinent portions of the veneerclipping machine with the knife of the clipper in a lowered position.

Fig. 2 shows a fragmentary side elevation view of the mechanism whichoperates the knife carriage;

Fig. 3 depicts a fragmentary side elevation taken along line 33 of Fig.1 showing an embodiment of the knife and anvil combination making up theveneer cutting station with the knife of the clipper in a raisedposition;

Fig. 4 which is similar to Fig. 3 shows another embodiment of the veneercutting station comprising the knife and anvil combination;

Fig. 5 is an enlarged cross-sectional View showing a substantiallysquare edge type of knife blade; and

Fig. 6 shows another anvil and knife combination.

Referring to Figs. 1, 2 and 3, 1L and 1R are side frame means comprisedof steel plates having structural transverse members not shown formaintaining the frame rigid and to enable the veneer cutting stationcomprising anvil 2 and knife carriage 3 with knife blade 4 to besuitably supported, the neck 2a of the anvil being held rigidly inchannel 5 by adjustable bolts 6 and 7, the channel in turn beingadjustably bolted to I-beam 8 adequately supported by a foundation, alsonot shown;

Fig. l which is a plan view of the clipper shows a plurality of parallelpulley driven belts, for example 9 and 10 on pulleys 9a and 10a, on asuitably driven rotatable shaft 11, adapted to deliver veneer sheets tothe cutting station, and another set of parallel belts, for example 12and 13 going around pulleys 12a and 13a mounted on rotatable shaft 14,adapted to carry cut sheets away from said station. Generally, fourbelts side by side are employed on each side of the station to deliverand carry the veneer sheets to and from it. The veneer travels throughthe machine in a substantially straight line.

a J Knife carriage 3 is constructed of heavy thick-walled cylindricalsleeve 15 which supports the knife blade about oseillatable stub shafts16L and 16R via a pinrality of transverse structural' 'arm members 17,the arms extending fromjthe'carriage "sleeve to points next to but abovethe'anvil as shown inFig. 3. The sleeve is fitted and keyed'to the stubshafts'at theirreduced end portions. At the'end of the arms 17,transverse member '18 'is provided to rigidize the carriage viastiffening 'Webs 20 as shown. As can'be seen in Fig. 3,'knife 4is'secured in a proper position on the carriage by means of bolts whichenable the knife to be moved to adjusted positions on the carriage.

Arms 17 extend between'the knife and sleeve 15 and are substantiallyparallel to the line of travel'of the veneer. The axis of rotation ofsleeve 15 is only slightly above the line of travel of the veneer'andsubstantially closer to the plane of said veneer than to a verticalplane passed through the knife. in i The sleeve of the carriage has astrong back 22 which serves to further stiffen the assembly, to stablizethe movement of the carriage and keep it substantially in balance as itis rocked by oscillating stub 'shafts 16L and 16R. Member 22 issubstantially coplanar with the axis of sleeve 15 and acts as acounterweight for the knife and carriage. The counterweight is fastenedto the opposite side of sleeve 15 from the knife and is elongated in thehorizontal direction so as to lie completely within the confines offrame members 1L and IR. It will be seen that no additional head room isrequired 'by this construction. The stub shafts may have adiameterranging from about 2 /2 to 3 inches or more. The weight of thecylindrical'sleeve 15 together with 'the strong back of the carriagemaintains the center of gravityof the knife carriage as near as possibleto the stub shafts and the sleeve, thus making the carriage easy to rockand control.

The stub shafts are oscillated by means of double acting compressed airor steam cylinders23L and 23R.

These'are rigidly attached to side frameslL and 1R (Figs. 1 and 2) withpiston rods 24L and 24R for the cylinders attached to link connectors orcrank pins 25L and 25R which in turn are pivotally connected toa togglejoint mechanism which'actuates the knife carriage.

The toggle joint mechanism includes two sets of paired,

upper toggle links indicated at 26L and 26R, respectively, and as shownmore clearly in Fig. 2, two sets of paired lower toggle links, comprisedof toggle link set 27L and 'a corresponding set of toggle links 'on theother side of the machine. The toggle structure on only one 'side' ofthe machine is discussed, since the actuating elements on the other sideare the same. Thus, the set of'toggle links 26L is pivotally connectedto hell crank 28L which is keyed to oscillatable stub shaft 16L at 29L.Toggle link set 27L is pivotally connected to toggle anchor 30L. Whenpiston rod 24L is caused to move towards the toggle links so as to alignthem substantially vertically, the bell crank moves counterclockwise ina direction to oscillate stub shaft "16L, which causes the carriage viathe keyed sleeve 15 to rock in the same direction to bring knife blade 4in cooperable relation with the anvil, as shown by the dotted lines inFig. 3.

Cylinder 23L is operated by air or high pressure steam passing throughpipe connections 31L and directed by T-connection 32L to suitablyoperated controlvalves 33L and 34L, for example solenoid controlledvalves, then through hose connections 35L,"36L to either- 'side of thecylinder. A similar arrangement employed for cylinder 23R. The controlvalves arejiop erated by switch means not shown to effect the change indirection of the pistons. Gene rally means cooperating with the movementof the knife are provided to reverse automatically the direction of thepiston rods after a cut has been made,

or if desired automatic means may be providedtorock the knife carriagein timed sequence to the travel of the veneer in accordance with thesize of the panel to be cut. In other words, the veneer clipper may bemade to operate manually or automatically or both.

The clipper provided by the invention has the advantage over prior arttypes in that it can be actuated by a small piston stroke. Foryexample,in the embodiment of Fig. 2, piston rod 24L can be operated at a stroke'of' fo'ur 'inches iris'tead" of six inches as-previously required,thereby 'efie ctingao'ne-third increase in speed, other things-beingequal. A'further increase in "speed is effected by making thedistance-from the 'togglepivot connection of crank pin 25L to the centerofstub shaft 16L one-half of that from the center ofstub shaft 16L toth'e'c'utting edgeofthe knife,thus effecting double increase in speed.As an example,-the first distance may be 5" and the second 10". Ifdesired, the speed ratio could be 1 /2 to l or 3 to 1 or even higher. Itis to 'be appreciated that the foregoingexamples are by-wayof'illustration and are not to be construed to limit the invention.

iAn enlarged view of'an embodiment of the knife '4 andganvilcombinationis shown in Fig. 5. The knife 4, which is generally referred to ashaving a square cornered edge, usually has a back draft or clearanceangle to enable it to move freely past and just below the top of anvil2. Aclearance angle of about 3 isadequate although the angle mayran'geup to about 5 or even- 10. The sides 2b and 2c of the anvil have aslight taper, the sides converging as they extend downwardly in Fig. 5.

In Fig.6, an embodimentof a knife and anvil combination is shown inwhichknife blade 4 has attached to it near the top by bolt 38 aresilient means, for ex- .ample a leaf spring 39 with a roller 40mounted at its free end, which is adapted to contact veneer sheet 37 onthe anvil before the knife reaches its cutting position so as to flattenthe sheet and hold it against the anvil in order to' further improve thecutting. 'Generally, the ,same'thing is accomplished by having aplurality of fingers spaced across the machine just before the sheetreaches the anvil so as to keep the sheet flat and in position forcutting. While the flow of portionsof a veneer sheet occupying thecutting station is stopped at the instant of cutting by the'knife blade,the moving sheet is cut so quickly that the remaining portions of thesheet 'outside the cutting stationare hardly affected other than byshowing a very slight ripple.

The anvil and the knife blade may be made of high alloy tool steel, forexample high speed steel. In the construction of the invention theseparts have an improved life and do not require as much maintenance asprior construction. I

'As shown in Figs. 3 and 4, veneer cutting may be effected in twopreferred ways. Thus, in Fig. 3 the square edge type of knife bladeprovides a nipping or shear type action adjacent the trailing edge ofthe anvil, i.e. the edge opposite the leading edge that the veneer sheetcrosses first on the anvil. In Fig. 4 the knife is sharply'pointed andmay be used to cooperate with the leading'edge of the 'anvil, althoughthe knife blade may also be used to cooperate with the trailing edge.

As hasbeen' stated hereinbefore, the advantages of the -machine are inits ease of handling and compactness, thusrequiring little head room. Ifdesired one or more machines can be placed one on top of the other todouble or even triple the production rate in the same area'nor- *mally'occupied by a prior machine requiring a lot of "head room. I

The expression veneerclipper as employed herein is meant to definegenerically a clipping device for cutting-'fiat sheet-Iike materialssuch as wood and-other products, for example hard card board,metal-sheets,

' etc.

'Whilethe present invention has been described in con- -'junctionwithpreferred-embodiments, it is to be understood that modifications-andvariations-may" be resorted to without departing'from the spirit andscope of the invention, as those skilled in the art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the invention and the appended claim.

I claim:

A veneer clipper comprising a frame, conveyor means mounted on saidframe for transporting veneer continuously thru the clipper along asubstantially horizontal path, a horizontal anvil member immovably fixedon the frame and mounted next to and below the path of travel of veneerthru the clipper and extending transversely of said path of travel,elongated shaft means rotatable about its longitudinal axis mounted onsaid frame next to and above the path of travel thru the clipper, saidshaft means extending substantially parallel to said anvil membe: butbeing offset to one side thereof, a knife parallel to said anvil memberconnected to said shaft means extending on one side thereof and abovesaid anvil member in cooperative cutting relationship therewith, acounter weight positioned above the path of travel of veneer andfastened to said shaft means on the opposite side thereof from saidknife, a reciprocating two-stroke motor means for actuating said shaftmeans, a stub shaft mounted on the end of said shaft means for rotationtherewith, a set of toggle links attached at the jointed end to saidmotor means, a crank attached to said stub shaft at one end and to oneof said toggle links at the other end, the other of said toggle linksbeing connected to said frame, whereby one stroke of said motor means isoperable to rotate said shaft means first in one direction and then theother with said knife moving downwardly toward and then returning fromsaid anvil member.

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